How to set particles' positions relative to the object in a behavior1k task?

[shengyin1224]

I find the json file for a task in a certain scene like Beechwood_0_int_task_clean_a_leather_belt_0_0_template.json.

I want to know how can I set the value for keys in "system_registry", like 'water', 'cloth' or 'dust'. For example, there may be 20 dust particles. How to give an accurate value of positions?

I find four obj states sampling functions -- fill, cover, soak, boil. Are these particles set by these sampling functions?